The light in my Jensen vent-a-hood is extremely dim. You can't even tell if it's on unless you turn out all the lights in the trailer. I looked at the bulb and it's a shiny silver/grey color. Does this mean it's burning out? I tried to put a 921 bulb from one of the overhead lights into the vent-a-hood and I can't get it to go into the socket even though when I put the 912 in the light fixture it seems to fit the same way. I even tried several different 921s in the vent-a-hood and they just won't go in.
1. Is there a trick to putting the 921 bulb in? (The 912 goes in and out with no trouble so I don't think it's the socket?
2. Would a new 912 be significantly brighter?
3. Should I just give up and live without a useful light at the stove?

When we received our trailer brand new it had been shown at an RV show where
the lights were all on for nearly 24 hours a day for 4 days. We also noted the stove
vent light was dim. I pulled it out and it was also silver colored. This happens because
some of the metal of the filament is actually vaporized and it condenses on the inside
of the bulb. This effectively renders the bulb nearly useless.

I swapped mine with a ceiling fixture.
Your 2 bulbs should be interchangeable.
The stove vent socket may be deformed, slightly melted or just a real tight fit.
It -should- fit.

After swapping mine, here we are nearly 5 years later and the bulb is still bright.
Some bulbs do this on occasion. Most do not.IF your 2 bulbs appear the same size base they can be swapped, you just have to
"force" it a little bit.
Might try looking carefully at the socket to be sure one of the contacts isn't bent
and blocking you from inserting the other bulb.